Don't know why you would cheese this fight anyway, it's one of the more interesting fights. If someone has a way to cheese a 20~ minute Sha of Fear HC, please tell me because that is boredom incarnate.

It probably was a kill, but RP phase did extend combat and logs just broke and registered 0.35 and 0.3 attempts after. But there is 0 healing on Tsulong in that long attempt. Thats very strange. And by the dps curves, it seems like they had just one 11 minute long night phase.

Looking at the logs I agree with that last statement. It even seems like they had a 11min long night phase where everyone was constantly standing in the Sunbeam, as noone, including tanks, took damage from the raidwide pulsing shadow dmg effect Dread Shadows.

Like someone above said though, they have the kill on heroic on their armories.
I'd find it difficult that a 4/16 guild could get h tsulong down without some kind of exploit/bug. They also got the meta achievement of keeping the tree alive for the entire fight

They need to strip the kills and loot from guilds that did this cheat. Problem solved, they didn't earn it

You realise most of the world 1-20 kills of Tsulong all involved an exploit? Almost all the world 1-20 kills consisted of bugs involving Rally Cry or the Druid 4 piece Dragon Soul bonus. Nothing happened to these guilds.

From the above, you can see that even though I gained Ancestral Guidance at 19:38:18, it wasn't until a Healing Surge at 19:38:23 that Ancestral Guidance triggered. Two sets of Restorative Mists' heals were applied in between those two events, but none triggered Ancestral Guidance.

The problem was Ring of Frost – being able to incapacitate an unlimited number of targets with a single spellcast caused problems. This ended up being a case where the negative cost of hotfixing the issue outweighed the upside of improving the encounter. When hotfixing spells, we do not have the ability to update the tooltips and other data that resides on each individual client. Thus, if we had added a target cap to the spell via hotfix, a mage who attempted to use it on a large pull in a dungeon, or a large group of players in a battleground, would have thought the spell was broken when it suddenly didn’t work on many of the targets. Quite simply, confusing hundreds of thousands of players in all sorts of contexts, in order to fix a problem in a situation affecting a few hundred players, was not an acceptable trade-off.

After 3 expansions of mages never really being 'bad' due to an amazing amount of focus on them by devs, are you really surprised by this?

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Does this change actually "screw shaman" outside of the Tsulong encounter?

Sure, in a way.
It always granted extra healing, just not as much due to the 1500% Buff of Tsulong and the Raiddesign. The broken Part was that healing done to pets by Ascendence (which was free of penalty) also triggered the extra healing. Now it doesnt work together completly.

you could argue that there were like three mages in the world, who outside of WotE used Ring of frost to cc more than 5 mobs for 10 secs on a regular basis and would have realised that i got nerfed.

Anybody care to comment how significant this is outside of the Tsulong encounter?

Not big, because Healing Stream Totem is nearly always the better choice for resto shamans. Bad balanced Talent tier.
But they should have fixed the boss without having to change the class, what their bluepost states they normally do.

I agree with the above posts, this "hotfix' doesn't screw shamans due to the talents (either AG or HTT). Having said that, I think Blizzard could have done it better.
e.g Made AG not proc off pet healing from Ascendance, but still allowed to proc off target healing aka raid.

This would make the spells work together if they ever become a better choice in the future, but still fixes the exploit on Tsulong.

Looking at the logs I agree with that last statement. It even seems like they had a 11min long night phase where everyone was constantly standing in the Sunbeam, as noone, including tanks, took damage from the raidwide pulsing shadow dmg effect Dread Shadows.

Something be fishy about this one.

There is a random bug that can very rarely occur: he gets stuck in night phase from the very start of the fight and doesn't really use any abilities, not even the pulsing AoE damage. We've previously encountered this once but reset the fight because it was just a lame way to do the boss, but in theory it would've been entirely doable from 100% to 0% since it's pretty much tank-and-spank. No idea what causes it to occur, and we've never seen it occur again.